1. Field
Example embodiments relate to a capacitor and a method of forming the capacitor. More particularly, example embodiments relate to a capacitor having lower electrodes stacked on each other and a method of forming the same.
2. Discussion of the Related Art
As semiconductor devices are highly integrated, a size of a unit cell of the semiconductor device is greatly reduced. However, a capacitor formed in the reduced unit cell is required to have a relatively high capacitance. Accordingly, in order to meet a required high capacitance in a unit cell of reduced size, various capacitor structures capable of increasing an effective area of an electrode included in the capacitor have been researched. Examples of the capacitor structures may be a planar type capacitor, a stack type or trench type capacitor, a cylinder type capacitor, etc.
However, when a height of a lower electrode of the cylinder type capacitor is increased, the lower electrode may incline or slant due to an unstable shape of the lower electrode. As a result, adjacent lower electrodes may be electrically connected to each other so that a bridge failure between the adjacent lower electrodes occurs frequently.
Accordingly, there is a need for a capacitor having a highly stacked structure that is stable enough to prevent falling down or slanting in a unit cell of reduced size, wherein the capacitor includes an electrode with a relatively large surface area.